Strangeways Prison
Thomas Woodhulme, 27, and William Henderson, 34, were both found not guilty of causing actual bodily harm to a HMP Manchester (Strangeways) prisoner. AFP/Getty

Two prison officers have been found not guilty of assaulting a prisoner who attempted to throw a bucket of human excrement at them.

Thomas Woodhulme, 27, and William Henderson, 34, were charged with causing actual bodily harm to inmate Nigel Halfacre at Manchester Crown Court.

They were accused of dragging Halfacre into his cell and assaulting him when he refused to place down the bucket during the incident in March last year.

But after a week-long trial a jury cleared the two men after hearing that Halfacre was under the influence of synthetic cannabis - known as Spice - at the time.

Halfacre told jurors he was paid £100 ($141) worth of the drug by another inmate at HMP Manchester, commonly known as Strangeways to throw the excrement and urine, known as "potting".

The jury heard that Halfacre, an inmate on the prison's B wing, had been relocated from HMP Altcourse in Merseyside when he was jailed for 16 weeks for "potting" another officer.

The court heard prosecutors say that a senior prison officer working that day was "shocked by what she saw the defendants do" according to the Manchester Evening News.

The court was told that Henderson, from Mossley, Tameside, had served in the Royal Navy, as a submariner for eight years, and Woodhulme, from Widnes in Cheshire, was previously a former professional rugby player.

The pair denied ever assaulting Halfacre and said they moved him to a cell to prevent the incident from becoming a "spectacle" for other inmates.

Henderson, a married father-of-one, denied holding down the inmate for him to be attacked and stated that he believed his actions were necessary.

Woodhulme, a father-of-four, admitted kicking the back of Halfacre's legs in order to force him to the floor.

But he told the court that he felt "justified" in doing so as the prisoner had refused to put the bucket down.

He added that the atmosphere before the incident was "bad" because a lack of staff meant inmates were kept in the cells for longer than usual.

The Manchester Evening News also reported that Woodhulme said he thought management at the prison "could have done more to alleviate this problem".